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April 28, 2009

Dinosaur bones offer new extinction theory

by Sam Savage

A U.S. scientist says he's found evidence dinosaurs may have survived for 500,000 years in New Mexico and Colorado after the Cretaceous extinctions.

Jim Fassett, an emeritus scientist with the U.S. Geological Survey in Santa Fe, N.M., said he based his conclusions on detailed chemical investigations of the dinosaur bones, and evidence for the age of the rocks in which they were found in the Ojo Alamo Sandstone in the San Juan Basin.

The great difficulty with this hypothesis -- that these are the remains of dinosaurs that survived -- is ruling out the possibility that the bones date from before the extinction, Fassett said. After being killed and deposited in sands and muds, it is possible for bones to be exhumed by rivers and then incorporated into younger rocks. But he said he has amassed a range of evidence that indicates the fossils from the Ojo Alamo Sandstone were not exhumed and re-deposited and that dinosaurs really did live after the end Cretaceous extinction event.

The controversial research appears in the journal Palaeontologia Electronica.